1. Field of the Invention
The present invention relates generally to wrapper materials for smoking articles. In particular the wrappers of the present invention are especially useful in conjunction with smoking articles that include a fuel element rather than conventional cigarettes containing a tobacco rod that is wrapped and burned. Such smoking articles are described, for example, in published European patent application No. 85111467.8 assigned to R. J. Reynolds. Although this European published application describes the use of conventional cigarette papers as wrappers, the requirements for such smoking articles are such that it would be advantageous to include a wrapper that will provide sufficient strength to maintain the assembly of components and that provides burn properties and appearance similar to those of conventional cigarettes. Since such articles do not burn tobacco rods in the conventional sense, it is also very desirable that the wrapper have good burn integrity to maintain the ash of the smoking article.
2. Description of the Prior Art
One description of a smoking article containing a burn fuel element is contained in the above-identified European patent application No. 85111467.8. However, this description refers only to the use of conventional cigarette papers as wrappers, and in use such conventional materials tend to lack adequate strength to maintain the assembly of components and lack the desirable burn properties such as appearance and ash integrity needed to provide optimum performance of the smoking article. It is also known to use finely divided clays such as attapulgite clay in tobacco smoking compositions as described, for example, in U.S. Pat. No. 3,049,449 to Allegrini dated Aug. 14, 1962. Furthermore, the use of high temperature resistant fibers in smoking article wrappers has been described, for example, in U.S. Pat. No. 4,433,697 to Cline and Owens dated Feb. 28, 1984. Burn enhancers such as alkali metal salts are, moreover, known for use in smoking article wrappers as described in U.S. Pat. No. 4,461,311 to Mathews, DeLucia, and Mattina dated July 24, 1984. Finally, smoking articles having double wrapped constructions are described in a number of patents, many of which are listed in U.S. Pat. No. 4,561,454 to Guess dated Dec. 31, 1985 which, itself, relates to a double wrapped smoking article.
In spite of such teachings it remains desired to improve the properties of specialty smoking articles having a fuel element to provide better appearance, integrity of the individual components, and improved burn properties.